<template>
  <div class="app-container">
    <!--查询表单-->
    <el-form :inline="true" class="demo-form-inline">

      <!-- 所属分类：级联下拉列表 -->
      <!-- 一级分类 -->
      <el-form-item label="课程类别">
        <el-cascader
          v-model="subjectIDS"
          placeholder="试试搜索：java"
          expand-trigger="hover"
          :options="subjectList"
          :props="defaultProps"
          :change="changAllSubjectId()"
          filterable>
          <template slot-scope="{ node, data }">
            <span>{{ data.title }}</span>
            <span v-if="!node.isLeaf"> ({{ data.children.length }}) </span>
          </template>
        </el-cascader>

      </el-form-item>

      <!-- 标题 -->
      <el-form-item>
        <el-input v-model="searchObj.title" placeholder="课程标题"/>
      </el-form-item>
      <!-- 讲师 -->
      <el-form-item>
        <el-select
          v-model="searchObj.teacherId"
          filterable
          placeholder="请选择讲师">
          <el-option
            v-for="teacher in teacherList"
            :key="teacher.id"
            :label="teacher.name"
            :value="teacher.id"/>
        </el-select>
      </el-form-item>

      <el-button type="primary" icon="el-icon-search" @click="fetchData()">查询</el-button>
      <el-button type="default" @click="resetData()">清空</el-button>
    </el-form>

    <!-- 表格 -->
    <el-table
      v-loading="listLoading"
      :data="list"
      element-loading-text="数据加载中"
      border
      fit
      highlight-current-row
      row-class-name="myClassList">

      <el-table-column
        label="序号"
        width="70"
        align="center">
        <template slot-scope="scope">
          {{ (page - 1) * limit + scope.$index + 1 }}
        </template>
      </el-table-column>

      <el-table-column label="课程信息" width="470" align="center">
        <template slot-scope="scope">
          <div class="info">
            <div class="pic">
              <img :src="scope.row.cover" alt="scope.row.title" width="150px">
            </div>
            <div class="title">
              <router-link :to="'/course/info/'+scope.row.id">{{ scope.row.title }}</router-link>
              <p>{{ scope.row.lessonNum }}课时</p>
            </div>
          </div>

        </template>
      </el-table-column>


      <el-table-column label="分类" width="200" align="center" sortable>
        <template slot-scope="scope">
          {{ getSubjectTitle(scope.row.subjectParentId,scope.row.subjectId) }}
        </template>
      </el-table-column>
      <el-table-column label="教师" width="100" align="center" sortable>
        <template slot-scope="scope">
          {{ getTeacherName(scope.row.teacherId) }}
        </template>
      </el-table-column>
      <el-table-column label="价格" width="100" align="center">
        <template slot-scope="scope">
          {{ Number(scope.row.price) === 0 ? '免费' : '¥' + scope.row.price.toFixed(2) }}
        </template>
      </el-table-column>
      <el-table-column prop="buyCount" label="付费学员" width="100" align="center">
        <template slot-scope="scope">
          {{ scope.row.buyCount }}人
        </template>
      </el-table-column>
      <el-table-column prop="buyCount" label="状态" width="100" align="center" sortable>
        <template slot-scope="scope">
          {{ scope.row.status==='Draft'?'未发布':'已发布' }}
        </template>
      </el-table-column>
      <el-table-column label="创建时间" align="center">
        <template slot-scope="scope">
          {{ scope.row.gmtCreate.substr(0, 10) }}
        </template>
      </el-table-column>
      <el-table-column label="发布时间" align="center">
        <template slot-scope="scope">
          {{ scope.row.gmtModified.substr(0, 10) }}
        </template>
      </el-table-column>
      <el-table-column label="操作" width="150" align="center">
        <template slot-scope="scope">
          <router-link :to="'/course/info/'+scope.row.id">
            <el-button type="text" size="mini" icon="el-icon-edit">编辑课程信息</el-button>
          </router-link>
          <router-link :to="'/course/chapter/'+scope.row.id">
            <el-button type="text" size="mini" icon="el-icon-edit">编辑课程大纲</el-button>
          </router-link>
          <el-button type="text" size="mini" icon="el-icon-delete" @click="removeDataById(scope.row.id)">删除</el-button>
        </template>
      </el-table-column>
    </el-table>

    <!-- 分页 -->
    <el-pagination
      :current-page="page"
      :page-size="limit"
      :total="total"
      style="padding: 30px 0; text-align: center;"
      layout="total, prev, pager, next, jumper"
      @current-change="fetchData"
    />

  </div>
</template>

<script>
  import course from '@/api/edu/course'
  import teacher from '@/api/edu/teacher'
  import subject from '@/api/edu/subject'

  export default {
    data() {
      return {
        listLoading: true// 是否显示loading信息
        , list: null // 数据列表
        , total: 0 // 总记录数
        , page: 1 // 页码
        , limit: 10 // 每页记录数
        , searchObj: {
          subjectParentId: '',
          subjectId: '',
          title: '',
          teacherId: ''
        } // 查询条件
        , teacherList: [] // 讲师列表
        , subjectList: []
        , defaultProps: {//联级选择器
          children: 'children',
          label: 'title',
          value: 'id'//要存个id
        }
        , subjectIDS: [] //绑定一级和二级分类id [0]为一级 [1]为二级
      }
    },
    computed: {
      //1. teacherList中获取教师名称
      getTeacherName() {
        return teacherId => {
          const teacher = this.teacherList.find(x => x.id === teacherId)
          return teacher ? teacher.name : ''
        }
      },
      //2. subjectList中获取分类名称
      getSubjectTitle() {
        return (subjectParentId, subjectId) => {
          const subjectParen = this.subjectList.find(x => x.id === subjectParentId)
          if (subjectParen) {
            const subject = subjectParen.children.find(x => x.id === subjectId)
            if (subject) {
              return subjectParen.title + ' / ' + subject.title
            } else {
              return subjectParen.title + ' / '
            }
          } else {
            return ''
          }
        }
      }

    },
    created() { // 当页面加载时获取数据
      this.fetchData()
      // 初始化分类列表
      this.initSubjectList()
      // 获取讲师列表
      this.initTeacherList()

    },
    methods: {
      //1. 获取分页带查询条件的列表
      fetchData(page = 1) { // 调用api层获取数据库中的数据
        console.log('加载列表')
        // 当点击分页组件的切换按钮的时候，会传输一个当前页码的参数page
        // 解决分页无效问题
        this.page = page
        this.listLoading = true
        course.getPageList(this.page, this.limit, this.searchObj).then(response => {
          // ////debugger 设置断点调试
          if (response.success === true) {
            this.list = response.data.rows
            this.total = response.data.total
          }
          this.listLoading = false
        })
      },
      //2. 级联选择器 节点变化时触发
      changAllSubjectId() {
        this.searchObj.subjectParentId = this.subjectIDS[0]
        this.searchObj.subjectId = this.subjectIDS[1]
      },
      //3. 初始化教师列表
      initTeacherList() {
        teacher.getList().then(response => {
          this.teacherList = response.data
        })
      },
      //4. 初始化分类列表 嵌套
      initSubjectList() {
        subject.getNestedTreeList().then(result => {
          this.subjectList = result.data
        })
      },
      //5. 重置表单数据
      resetData() {
        this.searchObj = {}
        this.subjectIDS = []
        this.fetchData()
      },
      //6. 删除课程
      removeDataById(id) {
        // ////debugger
        this.$confirm('此操作将永久删除该课程，以及该课程下的章节和视频，是否继续?', '提示', {
          confirmButtonText: '确定',
          cancelButtonText: '取消',
          type: 'warning'
        }).then(() => {
          return course.removeById(id)
        }).then(() => {
          this.fetchData()
          this.$message.success('删除成功')
        }).catch((response) => { // 失败
          if (response === 'cancel') {
            this.$message.info('已取消删除')
          } else {

          }
        })
      }
    }
  }
</script>

<style scoped>
  .myClassList .info {
    width: 450px;
    overflow: hidden;
  }

  .myClassList .info .pic {
    width: 150px;
    height: 90px;
    overflow: hidden;
    float: left;
  }

  .myClassList .info .pic a {
    display: block;
    width: 100%;
    height: 100%;
    margin: 0;
    padding: 0;
  }

  .myClassList .info .pic img {
    display: block;
    width: 100%;
  }

  .myClassList td .info .title {
    width: 280px;
    float: right;
    height: 90px;
  }

  .myClassList td .info .title a {
    display: block;
    height: 48px;
    line-height: 24px;
    overflow: hidden;
    color: #00baf2;
    margin-bottom: 12px;
  }

  .myClassList td .info .title p {
    line-height: 20px;
    margin-top: 5px;
    color: #818181;
  }
</style>
